Radiotelegraphy



- RADIOTELEGRAPHY.

' APPLICATION FILED APR.23.1911. 1,330,254. Patented Feb. 10,1920.

WITNESS INVENTOR.

H45 ATTORNEYS UNITED. STATES PATENT OFFICE.

LEONARD F. FULLER, or SAN FRANCISCO, CALIFORNIA, Assrcrron. r0 FEDERAL TELEGRAPH: COMPANY, OF SAN FRANCISCO, vCALIEOIlEtNIA, A

OF CALIFORNIA.

CORPORATION nnmo'rnnnennrny.

' Specification ofLetters Patent. Patented Feb. 1 0;1920.

Application filed April 23; 1917. Serial No. 163,793.

To all whom it may Concern:

Be. it known that I, LEONARD F. FULLER a citizen of the United States, and a residentof the city and county of San Francisco and State of California, have invented certain new anel'us'eful Improvements in Radiotelegraphy, of which the following is a specification.

The invention relates to means of signaling and particularly to means for signaling with are radio transmitters.

An object of the invention is to provide a signaling apparatus for high powered stations.

Another object of the invention isto provide means of signaling by'manipulatingthe direct current circuit. 7

The invention possesses other advanta geous features, some of which, with the foregoing, will be set forth at length inthe following description, where I shall outline in full that form of the invention which I have selected for illustration in the drawings accom anying and forming part of the present specification. It is to be understood, however, that the invention as expressed in the claims is not limited to the specific embodiments shown in the drawings.

Referring to said drawings: v

Figure 1 is a diagrammatic representation of one form of the system.

Fig. 2 is a diagrammatic representation of a modified form of the system.

Figs. 3 and 4 are diagrammatic representations of other forms of the s stem, showing other means of reigniting tlie arc. 4

Heretofore, as far as I am aware, it has been considered essential in arc radio transmitters, to kegs a practically constant radio- 40 on the are converter, when frequency lo This has been signals are being sent out.

accomplished in two ways; first, by the compensation method in w inductance-in the antenna circuit varied and second, by the absorbing circuit method, m

which a local non-radiating oscillatory cirich the arc is con-f" stantly loaded upon the antenna and' the for medium-powered stations, but they have complete'neglect of the other circuit.- Both shown certain disadvantages for high-powered stations, mainlybecause each requires the handling of radio-frequency currents at telegraphic speed.

My present invention provides a means of slgnalingwhich necessitates the handling at telegraphic speed of only the current which feeds theme, which may be direct current or alternating current, and this current maybe easily handled- In Fig. 1 I have shown one form of apparatus for signaling by manipulatmg the arc feeding current, which in this instance is direct current. The transmission system comprises a Poulsen arc oscillation generator 2 capable of producing continu- .ous oscillations, which is grounded on the negative side and'connect'ed on the positive a side to the antenna 3 through the variable antenna-inductance 4. Direct current is supplied to the arc by the generator 5, in the leads of which choke-coils 6 are placed. The arc is sub'ected. to a strong transverse magnetic fiel produced by the winding .7 arranged in the negative lead; shunting the arc is a circuit containing a variable resistance 8 and a make and break device comprising the. stationary electrode 9 and the movable electrode 12, the movable electrode being. connected to a suitable lever or key 13, which is used for signaling. A powerful transverse magnetic field is set up across the gap between the electrodes 9 and 12 for together, the are 2 is short-circuited by the resistance 8, which is so adjusted that the load on the generator -.5 remains the same as when the electrodes 9- and 12 were separated, and the are was burning and. "setting up the purpose of. quickly blowing out the D. C.

radio-frequency oscillations in'the antenna.

Thus the current in thearc magnet winding 7 is held constant, a feature which is necess sary on account of the large inductance ofthe winding. This large inductance sets up a large voltage across the arc gap and this voltage or inductive-kick, 'is sufficient to re- I ignite the are when the shunt circuit is opened. When the arc electrodes are cold, however, and there is no ionization of the gap due to the red-hot carbon, the arc will,

7 containing a condenser and the secondary of a step-up transformer 17 The primary of the transformer is included in a circuit 11 which is connected to the generator 20 Which may be a 5OQ-cyclcalternator. The circuit 11 is connected to the key 13 in such manner that ,the circuit 11 is closed, producing a spark across the are as the resistance circuit is opened. In this construction the electrode 12 is insulated from the key so that the resistance circuit and the ignition cir-- cuit are not connected.

In Fig. 3 I have shown a modified form of the system in which the resistance circuit is made and broken within the arc generator and the are produced by the. opening of the resistance circuit is employed for reigniting the main arc. In this arrangecontact with the positive electrode 18 of the arc, of the electrode 19 in the resistance circuit, and the electrode 19 is moved to open and close the resistance circuit by the key 21. As theresistance circuit is opened, an arc is produced between the electrodes 18 and 19 and this arc'bows out and is blown by the magnetic field into contact with the negative electrode 22, thereby reigniting themain are. In Fig. 4, the movable electrode 23 in the resistance circuit. isarranged to be moved'fiom the electrode 1 8 to the electrode 22, and viceversa, thereby breaking or making the main arc. When the electrode 23 -method of signaling which I have previ- *ously described, it is not possible, in practice, 'to receive while the arc is oscillating upon the local absorbing circuit for the reason that the circuit radiates suflicient energy to disturb the sensitive receiver.

I claim: L V

1. An are system for radio signaling,

comprising an arc, a current supply and an antenna c1rcu1t connected to the arc and .means for interrupting the arc while main-. taming the load on the-current supply substantially constant. i

'2. An are system for radio signaling comprisingan arc, an antenna circuit con-' nected to the arc and a resistance circuit shunted across the are, a source of. current supply connected to the arc and means for causing the current suppl to traverse the resistance circuit and there y extinguish the arc.

3. An are system for radio. signaling, comprising an arc, an antenna circuit connectedto thearc, and a resistance circuit shunted across the arc, a source of current supply connected to the arc, and a switch in the resistance circuit, the resistance in said circuit being such that when the switch is closed, the arc is extinguished and the load on the current supply remains substantially constant.

4. An arc. system for radio signaling, comprising an arc, an antenna circuit con-' 90. nected to the arc, and a resistance circuit shunted across the arc, a source of current supply connected to the arc, and means for ment, the resistance c1rcu1t is completed by varying the current in the resistance circuit to extlnguish the arc while maintaining the. current supply substantially constant.

5. An are system for radio signaling comprising an arc, an .antenna circuit con-. nected to. the arc and a resistance circuit. shunted across the arc, a source of current supply connected to the arc, and means for closing the resistance circuit to transfer the load from the antenna circuit to the resistance circuit, the resistance of the resistance circuit being such that the closing of said .105 circuit extinguishes the arc and maintains the load on the current supply substantially constant. o I 6. An arc. system for radio signaling comprlslng an are, an antenna circuit c0n-. nected to the arc and a resistance circuit shunted across'the are, a source of current supply connected to the arc,.a key for opening and closing the resistance circuit, means for producing a magnetic flux across the opening in the circuit, and means connected to the key for igniting the are as the resist ance circuit is opened. 7 c

Z. An are system for radio signaling, comprlsmg an are, a current su ply andan 1 antenna circuit connected to the arc, and

'means for extinguishing and reigniting the arc while'maintaining the load on the current supply substantially constant.

8.'The method of producing radio signals with an are supplied with current, wh ch consists in interrupting the arc and mainta ning the load on the current supply substantially constant. I

9. The method of producing radio signals with an are supplied with current, which consists in shunting the current around the arc and maintaining sald current substan tially constant.

10. The method of producing radio signals with an are supplied with current, which consists in shunting the current around the arc to extinguish the arc While maintaining said current substantially constant and opening the shunt circuit and Ife- 10 LEONARD F. FULLER.

In presence of H. G. Pnos'rl 

